When opening the page's file in website x5, it was the only file where I couldn't change the page type, which was php, to anything else (the type dropdown menu was disabled). It only contained a product catalog component. If I copy-pasted it to another page, then the other page would return the error as well. However, if I added a new product catalog (and delete the previously copied one), then the page would work.

As of now, I could make it work by making a new html version of the page and readding the content.

Anyway, I think it is a bug, and could happen to other people, so if you know a solution, please tell me.